I have an annotate box in my chart, and it will go missing if I zoom in or look at other segment of the variable range of one of the axis. Can anyone tell me how to make the annotate box always show up at a fixed position, no matter how I change the chart/table?

If you can wait until 8.1 (coming very soon! ) this will be very easy using floating, transparent text boxes. Otherwise, you might use a text box on a dashboard that does not overlap the chart to display what you want to keep fixed.